Childhood cancer survivors are at increased risk for chronic health conditions that may be influenced by their cancer treatment and unhealthy lifestyle behaviors. Despite the possibility that interventions targeting the survivor-parent dyad may hold promise for this population, a clearer understanding of the role of family factors and the lifestyle behaviors of both survivors and parents is needed. A mailed cross-sectional survey was conducted in 2009 to assess weight status (body mass index), lifestyle behaviors (eg, diet, physical activity), and the quality of the parent-child relationship among 170 childhood cancer survivors who were treated at MD Anderson Cancer Center and 114 of their parents (80% mothers). Survivors were more physically active and consumed more fruits and vegetables than their parents. However, fewer than half of survivors or parents met national guidelines for diet and physical activity, and their weight status and fat intakes were moderately correlated (r=30-57; P<0.001). Multilevel models showed that, compared with survivors with better than average relationships, those with poorer than average relationships with their parents were significantly more likely to consume high-fat diets (P<0.05). Survivors and their parents may thus benefit from interventions that address common lifestyle behaviors, as well as issues in the family environment that may contribute to an unhealthy lifestyle. © 2011 American Dietetic Association.